Grove MB2

There are two types of Aircraft Pushback Tractors: conventional and towbarless (TBL).
Conventional tugs use tow bars to connect to the nose wheel of the aircraft.
The tow bar can be connected at the front or the rear of the tractor, depending on whether the aircraft will be pushed or pulled.
The towbar has a shear pin.
The shear pin prevents the aircraft from being mishandled by the tug—when overstressed
the shear pin will snap, disconnecting the bar from the nose gear to prevent damage to the aircraft and tug.